Understanding the maximum dynamical heterogeneity during the unfreezing process in metallic glasses

The dynamic behaviors displayed during the unfreezing process of metallic glasses are investigated using molecular dynamics simulations. The non-monotonic variation of dynamical heterogeneity as temperature increases can be understood microscopically by the flow unit perspective. This variation of dynamical heterogeneity exhibits a peak at the temperature T α 2 , max below the related α-relaxation temperature. Meanwhile, the T α 2 , max signaling the maximum dynamical heterogeneity is found to be the onset temperature at which the largest activated cluster starts to present the percolation property. Our results give hints to the understanding of low temperature relaxation and the related correlation with α relaxation in metallic glasses.